From Heretics by GK Chesterton - 1905:
Many of the most brilliant intellects of our time have urged us to ... self-conscious snatching at a rare delight.
Walter Pater said that we were all under sentence of death, and the only course was to enjoy exquisite moments simply for those moments' sake. The same lesson was taught by the very powerful and very desolate philosophy of Oscar Wilde.
It is the carpe diem religion; but the carpe diem religion is not the religion of happy people, but of very unhappy people.
Great joy does, not gather the rosebuds while it may; its eyes are fixed on the immortal rose which Dante saw. Great joy has in it the sense of immortality; the very splendour of youth is the sense that it has all space to stretch its legs in. In all great comic literature, in "Tristram Shandy" or "Pickwick", there is this sense of space and incorruptibility; we feel the characters are deathless people in an endless tale.
It is true enough, of course, that a pungent happiness comes chiefly in certain passing moments; but it is not true that we should think of them as passing, or enjoy them simply "for those moments' sake." To do this is to rationalize the happiness, and therefore to destroy it.
Happiness is a mystery like religion, and should never be rationalized. Suppose a man experiences a really splendid moment of pleasure. I do not mean something connected with a bit of enamel, I mean something with a violent happiness in it--an almost painful happiness.
A man may have, for instance, a moment of ecstasy in first love, or a moment of victory in battle. The lover enjoys the moment, but precisely not for the moment's sake. He enjoys it for the woman's sake, or his own sake. The warrior enjoys the moment, but not for the sake of the moment; he enjoys it for the sake of the flag.
The cause which the flag stands for may be foolish and fleeting; the love may be calf-love, and last a week. But the patriot thinks of the flag as eternal; the lover thinks of his love as something that cannot end.
These moments are filled with eternity; these moments are joyful because they do not seem momentary.
Once look at them as moments after Pater's manner, and they become as cold as Pater and his style.
Man cannot love mortal things. He can only love immortal things for an instant.